1. Field of the Invention
The present invention relates to novel azobenzene derivative compounds, particles formed by aggregates of said azobenzene derivative compounds and method of fabricating the same.
2. Discussion of the Background
Azobenzene is known not to be emissive at room temperature. Accordingly, it has been proposed that metals or emissive substances be introduced into azobenzene to obtain emissive azobenzene derivatives (Yutaka, T.; Mori, I.; Kurihara, M.; Mizutani, J.; Tamai, N.; Kawai, T.; Irie, M.; Nishihara, H. Inorg. Chem. 2002, 41, 7143., Aiello, I.; Ghedini, M.; Deda, M. D. J. Lumin. 2002, 96, 249. Ghedini, M.; Pucci, D.; Calogero, G.; Barigelletti, F. Chem. Phys. Lett. 1997, 267, 341. Nihei, M.; Kurihara, M.; Mizutani, J.; Nishihara, H. J. Am. Chem. Soc. 2003, 125, 2964. Tsuchiya, S. J. Am. Chem. Soc. 1999, 121, 48.). However, these azobenzene derivatives have problems in the form of shifted absorption bands or reduced isomerization rates.
On the other hand, it has been reported that when a compound exhibiting weak fluorescence was added to a mixed solvent of water and an organic solvent to form aggregates (for example, nanometer-scale aggregates (nanoparticles)), an emission enhancement of several hundred times that which was present prior to aggregation was exhibited.
Generally, aggregates such as nanoparticles are formed by adding an amphiphilic substance having a hydrophilic moiety and a hydrophobic moiety to a mixed solvent of water and an organic solvent. However, amphiphilic substances have problems in that they are difficult both to synthesize and to purify.